This invention relates to a technique for preventing peel of a package interface and crack when a surface package type semiconductor package is mounted to a packaging substrate such as a printed circuit board.
In surface mount package type semiconductor packages such as a small outline package (SOP), a squad flat package (QFP), a plastic leaded chip carrier (PLCC), and the like, the size and thickness of the packages are more and more reduced in order to cope with the increase in the size of a semiconductor chip stored in the package and package strength tends to decrease.
Therefore, it has become difficult to produce a thin resin molded IC having high reliability.
Incidentally, mention can be made of xe2x80x9cIC PACKAGING TECHNIQUExe2x80x9d, published by Kogyo Chosakai K. K., Jan. 15, 1980, pp. 135-156, as a prior art reference describing surface package type semiconductor packages.
Furthermore, as disclosed in Japanese Patent Laid-Open No. 178877/1986 by Otsuka et al. (Aug. 11, 1986), a proposal has been made to put a desiccant into a magazine or to seal a conveying tray in a bag of a vinyl sheet or the like.
When examining packaging reliability and strength of these thin type packages, the inventors of the present invention have found out that when heat is applied to the package when surface-mounting the package to a mounting substrate such as a printed circuit board such as at the time of solder reflow, a moisture that has entered the package causes drastic volume expansion and peel of the package interface and crack develops.
To cope with this problem, it has been customary to bake the package at 125xc2x0 C., for example, for a period as long as 16 to 24 hours before solder reflow, but this method is believed inefficient because a furnace for baking must be prepared and particularly because baking must be made for the long period.
As a result of examination of the origin of the moisture causing the cracking described above, the inventors of the invention have clarified that the moisture in the air enters the package during the period from transfer molding of a chip component by a resin to solder reflow and is likely caused to dew.
Though the Otsuka et al. method described already provides a considerable effect, the problem cannot be solved completely by this method in view of the recent product situation where the thickness and size of the packages are reduced more and more to store greater chips and of the severe environment where the products are shipped by airplanes.
It is therefore an object of the present invention to provide a technique which prevents interface peeling and cracking of a surface mount package type package.
It is another object of the present invention to provide a highly reliable high density packaging technique.
It is still another object of the present invention to provide an efficient solder reflow technique.
It is still another object of the present invention to provide an effective shipment method of electronic components.
It is a further object of the present invention to provide an effective preservation method of semiconductor devices sealed by a thin resin package.
It is still another object of the present invention to provide high freedom for the conditions of executing an assembly process.
It is still another object of the present invention to provide an assembly process which will be suitable for surface mount package.
It is still another object of the present invention to provide an efficient surface mount type packaging technique.
It is still another object of the present invention to improve moisture-proofness of resin-molded ICs, or the like.
It is still another object of the present invention to provide a packaging technique of resin-molded ICs or the like which will be suitable for automatic packaging.
It is still another object of the present invention to provide a preservation method of ICs, components, electronic devices, and the like, which have high moisture-proofness and do not require baking even when stored for a long period.
It is still another object of the present invention to provide a packaging method of electronic components such as ICs which can easily discriminate the existence of pin-holes.
It is still another object of the present invention to provide a moisture-proofing package technique of ICs or the like which does not need a large space requirement.
It is still another object of the present invention to provide a moisture-proofing packaging technique of ICs or the like which can easily judge the degree of hygroscopicity of ICs or the like.
It is still another object of-the present invention to provide a moisture-proofing bag having a display portion for displaying the degree of hygroscopicity of ICs or the like.
It is still another object of the present invention to provide a package member for surface package type packages which can easily represent the degree of hygroscopicity of ICs or the like.
It is still another object of the present invention to provide an efficient surface mounting method of resin-molded ICs or the like.
It is still another object of the present invention to provide an assembly process which will be suitable for resin-molded electronic components storing therein integrated circuits having a large chip size.
It is still another object of the present invention to provide a shipment method of electronic devices such as resin-molded ICs which will-be suitable for the shipment of the electronic devices by air planes.
It is still another object of the present invention to provide a moisture-proofing packaging technique of resin-molded ICs or the like which does not undergo dewing even at low temperatures.
It is still another object of the present invention to provide a technique which can confirm the state of hygroscopicity of a moisture-proofing package inside the package from the outside thereof.
These and other objects and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
Among the inventions disclosed herein, a typical example is as follows.
In the present invention, a surface mount package type package stored in a magazine is put into an interior box, the interior box is then placed into a transparent resin bag using, as the base, a polyester having moisture permeability of up to 2.0/m2xc2x724 hrs, for example, and having a surface intrinsic resistance of 106 Ohms on the outside and up to 1011 Ohms on the inner side, and the open portion of the bag is heat-sealed after removing the air. Furthermore, a desiccant such as silica gel is put into the interior box.
According to this arrangement described above, the surface mount package type package is stored in the interior box and the moisture-proofing bag outside the box and sealed completely by deaeration and heat seal and is free from the influences of external moisture. Therefore, the interface peel and crack of the package do not occur even after solder reflow without the need of the troublesome baking operation. Particularly because the polyester having moisture permeability of up to 2.0 g/m2xc2x724 hours is used as the base of the resin bag in the present invention, moisture-proofness is high and heat seal is possible so that the effect of checking intrusion of the external air is high. The surface intrinsic resistance of the bag is up to 1011 ohms on its inner surface and up to 106 ohms on its outer surface in order to prevent any charge. Furthermore, silica gel is placed between the magazine and the wall surface of the interior box in the present invention in order to absorb the moisture so that the surface package type package is not much affected by the external moisture.
Still another example of the inventions disclosed herein is as follows.
Namely, the present invention provides a transparent moisture-proofing packaging bag for moisture-proofing and packaging an electronic component, which bag is equipped with a moisture indicator for detecting the degree of hygroscopicity inside the moisture-proofing bag at a portion which is visible from outside.
According to the means described above, since the moisture indicator for detecting the moisture inside the transparent moisture-proofing bag is disposed at a position visible from outside, the degree of hygroscopicity of the bag can be confirmed from outside the bag.
Still another typical example of the inventions disclosed herein provides a package which comprises a semiconductor chip on which at least one electronic device is formed, a resin-molding member covering at least a part of the main plane of the semiconductor chip, and a moisture-proofing bag comprising a multi-layered film containing at least one metal sheet, for cutting off the resin-molding member from outside.
Still another typical example of the inventions disclosed herein provides a package of a number of (about 10) resin-molded semiconductor devices which are stored in a plastic magazine, whose outside portion is sealed air-tight by a moisture-proofing film.
Still another typical example of the inventions disclosed herein provides an air-tight package made of a moisture-proofing film and including a number of resin-molded semiconductor devices, a plurality of device storing magazines storing therein a line of resin-molded semiconductor devices, an interior box for aligning a plurality of magazines and storing them therein while they are in close contact with one another, a packaging bag made of a moisture-proofing sheet member, storing therein the interior box and sealed air-tight, and a desiccant placed in the packaging bag.
Still another typical example of the inventions disclosed herein provide an air-tight package for a number of surface mount package type resin-molded semiconductor devices which comprises an exterior box made of a cardboard, a number (at least five to six) of packaging bags made of a moisture-proofing film and sealed air-tight, a plurality of interior boxes made of paper and stored in the packaging bag, a plurality of tube-like magazines for conveying semiconductor devices, stored in the interior boxes, respectively, a number of surface package type resin-molded semiconductor integrated circuit devices stored in the magazines, respectively, and a desiccant stored in each of the interior boxes.
Still another typical example of the inventions disclosed herein provides an air-tight package for a large number of surface mount package type resin-molded semiconductor integrated circuit devices which comprises an exterior box made of cardboard, a plurality of packaging bags made of a moisture-proofing film and sealed air-tight inside the exterior box, at least one conveying auxiliary member for protecting a number (at least five to six) of resin-molded semiconductor devices stored in the packaging bags, a number of resin-molded semiconductor integrated circuit devices stored in or on the auxiliary member, and a desiccant stored in each of the packaging boxes.
Still another typical example of the inventions disclosed herein provides an air-tight package for at least one resin-molded semiconductor device which comprises a packaging bag made of a moisture-proofing film, at least one conveying auxiliary member stored in the packaging bag, at least one resin-molded semiconductor device stored in the packaging bag and stored in or on the auxiliary member, and a desiccant placed in the packaging bag.
Still another typical example of the inventions disclosed herein provides an air-tight package for at least one resin-molded semiconductor device which comprises a packaging bag made of a moisture-proofing film and sealed air-tight, at least one resin-molded semiconductor device stored in the packaging bag, and a desiccant placed in the packaging bag.
Still an-other typical example of the inventions disclosed herein provides an air-tight package for at least one resin-molded semiconductor device which comprises a packaging bag made of a moisture-proofing film and sealed air-tight, at least one resin-molded semiconductor device stored in the packaging bag, and a desiccant stored in the packaging bag or formed on the inner surface of the packaging bag.
Still another typical example of the inventions disclosed herein provides a package comprising a semiconductor chip on which at least one electronic device is formed, a moisture-proofing bag for cutting off the semiconductor chip from outside, and humidity display means disposed in the moisture-proofing bag and capable of being recognized from inside.
Still another typical example of the inventions disclosed herein provides a package comprising a tube-like magazine for storing a line of a number (at least five to six) of resin-molded semiconductor devices, a number of resin-molded semiconductor devices stored in the magazine, and humidity display means disposed in the magazine in such a manner as to be visible from outside.
Still another typical example of the inventions disclosed herein provides a package for a large number (at least ten) of resin-molded semiconductor devices, sealed air-tight by a moisture-proofing film, said package being equipped thereinside with humidity display means in such a manner as to be visible from outside.
Still another typical example of the inventions disclosed herein provides an air-tight package made of a moisture-proofing film, which comprises a number of resin-molded semiconductor devices, a plurality of device storing magazines for storing therein a number of resin-molded semiconductor devices aligned in a line, an interior box for storing therein a plurality of magazines while being aligned and in close contact with one another, a packaging bag for storing therein the interior box, made of a moisture-proofing sheet and sealed air-tight, and humidity display means disposed inside the packaging bag in such a manner as to be visible from outside.
Still another typical example of the inventions disclosed herein provides an air-tight package for a number of surface package type resin-molded semiconductor integrated circuit devices, which comprises an exterior box made of cardboard, a number (at least five to six) of packaging bags made of a moisture-proofing film, sealed air-tight and stored in the exterior box, a plurality of interior boxes made of paper and stored in the packaging bag, a plurality of tube-like magazines for conveying semiconductor devices, stored in the interior boxes, respectively, a number of surface mount package type resin-molded semiconductor integrated circuit devices stored in a plurality of magazines, respectively, and humidity display means for displaying an internal humidity of said packaging bag, disposed inside the packaging bag in such a manner as to be visible from outside the packaging bag.
Still another typical example of the inventions disclosed herein provides an air-tight package for a number of surface package type resin-molded semiconductor integrated circuit devices which comprises an exterior box, a plurality of packaging bags made of a moisture-proofing bag and stored in the exterior box, at least one conveying auxiliary member for protecting a number (five to six) of resin-molded semiconductor devices stored in the packaging bag, a number of resin-molded semiconductor integrated circuit devices stored in or on the auxiliary member, and humidity display means for displaying the internal humidity of the packaging bag, disposed in the packaging bag in such a manner as to be visible from outside.
Still another typical example of the inventions disclosed herein provide an air-tight package for at least one resin-molded semiconductor device, which comprises a packaging bag made of a moisture-proofing film and sealed air-tight, at least one conveying auxiliary member stored in the packaging bag, at least one resin-molded semiconductor device stored in the packaging bag and stored in or on the auxiliary member, and humidity display means disposed in the packaging bag in such a manner as to be visible from outside.
Still another typical example of the inventions disclosed herein provides an air-tight package for at least one resin-molded semiconductor device, which comprises a packaging bag made of a moisture-proofing bag and sealed air-tight, at least one resin-.molded semiconductor device stored in the packaging bag, and humidity display means disposed in the packaging bag in such a manner as to be visible from outside.
Still another typical example of the inventions disclosed herein provides an air-tight package for at least one resin-molded semiconductor device, which comprises a packaging bag made of a moisture-proofing film and sealed air-tight, at least one resin-molded semiconductor device stored in the packaging bag, and a drying member stored or formed inside the packaging bag in such a manner as to be visible from outside.
Still another typical example of the inventions disclosed herein provides an air-tight package for a number of resin-molded semiconductor devices, which comprises a carrier tape made of a first moisture-proofing resin sheet and having device storing recesses, a plurality of resin-molded semiconductor devices stored in the recesses, and a second moisture-proofing resin sheet covering the upper surface of the recesses and sealed in such a manner as to keep the inside of the recesses air-tight.
Still another typical example of the inventions disclosed herein provides a packaging method of resin-molded semiconductor devices, which comprises the steps of preserving the resin-molded devices in a moisture-proofing bag lest they should absorb moisture, taking out the resin-molded devices from the moisture-proofing bag, and placing the resin-molded devices on a wiring substrate and soldering the leads of the resin-molded devices to the wirings on the wiring substrate under such a condition where the resin-molded portion receives thermal impact.
Still another typical example of the inventions disclosed herein provides a method of shipping a large number of resin-molded semiconductor devices by an air plane, which comprises sealing air-tight the resin-molded semiconductor devices together with a desiccant in a moisture-proofing bag.
Still another typical example of the inventions disclosed herein provides a method of fabricating resin-molded semiconductor devices, which comprises the steps of sealing a semiconductor chip and inner leads by a resin, putting an ink mark to the resulting resin-molded member, exposing the resin-molded member as a whole after marking to a high temperature for baking the ink, and sealing airtight the devices after completion before they absorb moisture.
Still another typical example of the inventions disclosed herein provides a method of fabricating a molded semiconductor memory device, which comprises the steps of fixing lead to semiconductor chip holding portions made of the same metal sheet as that of the leads through one of the main planes of the tip, bonding pads on the other main plane of the chip to inner leads by a bonding wire, coating an organic resin causing less occurrence of xcex1-rays on at least a region of the other main plane of the chip, where memory cells are formed, forming a resin-molded member from which a plurality of leads projects, by molding the chip, the wires, the chip holding members and the inner leads by a resin, and packaging the resin-molded member by a moisture-proofing bag lest the resin-molded member absorbs the moisture.